Long-term Vegetation Recovery Research Articles

Erasing anthropogenic disturbance: Natural revegetation of linear features following wildfire, and the implications for woodland caribou (Rangifer tarandus caribou) habitat management.

The federal recovery strategy for woodland caribou identifies wildfires within the last 40 years and anthropogenic disturbance visible at a scale of 1:50,000, including a 500-m buffer, as disturbed. Long-term vegetation recovery on linear features post-fire has not yet been documented. We examined vegetation recovery including stem density and height, hiding cover, and reindeer lichen cover along 40+ year-old legacy linear features in Northern Saskatchewan, in both uplands and lowlands 1–41 years post-fire. We compared these results with burned areas off-lines and unburned lines. On unburned lines in uplands there was minimal recovery, while there was significant recovery of stem count, height and hiding cover on burned lines and burned off-lines. Reindeer lichen cover and thickness remained significantly lower on burned lines and burned off-lines than on unburned lines until the 41-year age group, where there was no longer a significant difference. In lowlands, the stem density and stem height were initially significantly higher on unburned lines than on either burned lines or burned off-lines. After 27–32 years post-fire there was no longer a significant difference in stem densities. Our findings show that fires substantially accelerate natural revegetation and instigate a recovery that is similar on and off disturbance features in both uplands and lowlands. These findings can inform management decisions on restoration planning and calculation of range disturbance metrics. We suggest that the anthropogenic 500-m buffer should be removed post fire, as anthropogenic disturbance is reset, and anthropogenic disturbance should be classified as naturally recovering.

Soil transfer impacts restored soil profiles and hydrodynamic properties

Natural and semi-natural grasslands, particularly dry grasslands, are high-value biodiversity hotspots in Europe and major challenges for ecological conservation and restoration. Soil transfer has been used successfully to restore dry grassland ecosystems (soil and vegetation),but should only be applied as a last resort and where an undegraded ecosystem has previously independently been earmarked for destruction.Assessing overall restoration success means taking soil recovery into account as well as vegetation regeneration. In Mediterranean regions and under global warming, soil hydrodynamic properties are the most critical limiting factors for the restoration of dry ecosystems. This study analyses soil physico-chemical parameters and hydrodynamic properties in reconstructed soils after soil transfer following a petrol land spill. Six years after soil transfer and compared to the surrounding soil reference steppe, the horizons of the soil transfer treatments were significantly less colonised by plant roots and showed very few biological activities and earthworm galleries. Then, their porosity was also significantly lower. Hydrodynamic properties continue to differ significantly between the restored site and the surrounding reference steppe ecosystem. There is also less available soil water and water drains faster in all soil transfer treatments. This can be explained by significant higher finer grain size (clays, silt), chemical elements (N, P, K), and plant cover for soil transfer treatments but significant, lower levels of organic matterdue to mechanical soil compaction during soil spreading. The soil transfer treatment involving full reconstitution of the three main soil layers yields the most encouraging results. However, the question arises of whether long-term vegetation recovery might be compromised by soil hydrological dysfunction under global warming.

Post-fire vegetation succession in the Siberian subarctic tundra over 45 years

Wildfires are relatively rare in subarctic tundra ecosystems, but they can strongly change ecosystem properties. Short-term fire effects on subarctic tundra vegetation are well documented, but long-term vegetation recovery has been studied less. The frequency of tundra fires will increase with climate warming. Understanding the long-term effects of fire is necessary to predict future ecosystem changes.We used a space-for-time approach to assess vegetation recovery after fire over more than four decades. We studied soil and vegetation patterns on three large fire scars (>44, 28 and 12 years old) in dry, lichen-dominated forest tundra in Western Siberia. On 60 plots, we determined soil temperature and permafrost thaw depth, sampled vegetation and measured plant functional traits. We assessed trends in Normalized Difference Vegetation Index (NDVI) to support the field-based results on vegetation recovery.Soil temperature, permafrost thaw depth and total vegetation cover had recovered to pre-fire levels after >44 years, as well as total vegetation cover. In contrast, after >44 years, functional groups had not recovered to the pre-fire state. Burnt areas had lower lichen and higher bryophyte and shrub cover. The dominating shrub species, Betula nana, exhibited a higher vitality (higher specific leaf area and plant height) on burnt compared with control plots, suggesting a fire legacy effect in shrub growth. Our results confirm patterns of shrub encroachment after fire that were detected before in other parts of the Arctic and Subarctic.In the so far poorly studied Western Siberian forest tundra we demonstrate for the first time, long-term fire-legacies on the functional composition of relatively dry shrub- and lichen-dominated vegetation.

Prioritizing Research Needs in Natural Resources: Using Q-Methodology as a Focus Group Discussion Tool

Abstract Combining Q-methodology with focus groups offers a novel opportunity to explore how researchers and managers can collectively address natural resource management issues. We explored the potential utility of this pairing for prioritizing long-term vegetation recovery research needs after wildfire at a two-day workshop. The approach entailed individual Q-sort activities, followed by focus group discussion about differences and similarities in Q-sort outcomes between managers and researchers. We found that Q-methodology was a versatile discussion tool that offered opportunities for building shared definitions of management issues and identifying new pathways for collaboration between diverse participants. Group discussion around research needs also fostered opportunities for identifying organizational barriers and fostering partnerships to overcome them. Collecting social data on research needs prior to designing or conducting data collection efforts can help ensure that outputs have practical value and utility for land management. Study Implications Establishing shared research priorities between researchers and managers is one way to ensure that scientific advancements have practical applications. Using outputs from Q-sort activities as a prompt to initiate discussion between researchers and managers is an effective technique for understanding divergent prioritizations, identifying organizational and scientific barriers, and establishing feasible next steps for collective action to produce application-oriented research. Employing mixed-method social data collection early in the land management planning process is increasingly valuable; many recent policies for forest and natural resource management require the incorporation of collaborative components.

Long-Term Vegetation Recovery and Invasive Annual Suppression in Native and Introduced Postfire Seeding Treatments

Seed mixes used for postfire seeding in the Great Basin are often selected on the basis of short-term rehabilitation objectives, such as ability to rapidly establish and suppress invasive exotic annuals (e.g., cheatgrass, Bromus tectorum L.). Longer-term considerations are also important, including whether seeded plants persist, continue to suppress invasives, and promote recovery of desired vegetation. To better understand long-term effects of postfire seed mixes, we revisited study sites in Tintic Valley, Utah, where seeding experiments had been initiated after the 1999 Railroad wildfire. Four different mixes, including two comprised entirely of native species, had been applied using rangeland drills at a shrubland site and aerial seeding followed by one-way Ely chaining at a woodland site. New vegetation data collected 16 years post fire revealed changes relative to 3 years post fire. We found significant increases in total cover of seed-mix species in all treatments, including the unseeded control where these species were present as residual populations or had spread from seeded treatments. Significant increases of seed-mix species cover and density were observed in blocks where seeding treatments had previously been considered unsuccessful. Some seed-mix species, particularly rhizomatous grasses, increased while others declined. Exotic annual forb cover decreased in all treatments while cheatgrass increased in the unseeded control and to a lesser extent in the native-only seeded treatments. Recruitment of non-seed-mix native perennials was highest in the unseeded control. Results indicate that postfire seeding has lasting effects on vegetation composition and structure, implying that seed mixes should be carefully formulated to promote long-term management objectives. Seed mixes containing large amounts of competitive introduced species may be especially effective for long-term cheatgrass suppression, but native-only mixes can also serve this purpose to a lesser degree while avoiding drawbacks of non-native species introductions.

Differential responses of litter decomposition to nutrient addition and soil water availability with long-term vegetation recovery

The litter decomposition, nutrient patterns, as well as nutrient release and soil nutrient contents were determined in response to nitrogen (N) and phosphorus (P) addition and drought treatments following long-term vegetation recovery. The litter decomposition rate decreased with vegetation recovery, due to changes in litter quality, soil nutrient availability, and soil enzyme activity. Nitrogen addition promoted litter decomposition in the early recovery stages but inhibited decomposition in the later stages, indicating a shift in the nutrient limitations to litter decomposition with succession. Neither N nor P addition had any effect on the release of litter carbon (C), whereas N addition inhibited litter N release. In addition, drought decreased litter decomposition and nutrient release during the vegetation recovery process. Our findings suggest that litter quality, soil nutrient availability, and moisture at different vegetation recovery stages should be considered when modeling the C cycle and nutrient dynamics in these ecosystems.

A Long-Term Vegetation Recovery Estimation for Mt. Jou-Jou Using Multi-Date SPOT 1, 2, and 4 Images

Vegetation recovery monitoring is critical for assessing denudation areas after landslides have occurred. A long-term and broad area investigation using remote sensing techniques is an efficient and cost-effective approach incorporating the consideration of radiometric correction and seasonality variations across multi-date satellite images. This paper investigates long-term vegetation recovery using 14 SPOT satellite images spanning from 1999 to 2011 over the landslide area of Mt. Jou-Jou in central Taiwan, which was caused by the Chi-Chi earthquake in 1999. The vegetation status was evaluated by the Normalized Difference Vegetation Index (NDVI) with radiometric correction between multi-date images based on pseudoinvariant features, and subsequently a vegetation recovery rate (VRR) model was empirically established after seasonality adjustment was performed on the multi-date NDVI images. An increasing tendency of the vegetation recovery in the landslide area of Mt. Jou-Jou appeared based on the NDVI value rising to 0.367 in March 2011 from −0.044 right after the catastrophic earthquake. The vegetation recovery rate with seasonality adjustment approached 81.5% for the total area and 81.3% for the landslide area through 12 years succession. The seasonality adjustment also enhanced the VRR model with a determination coefficient that increased from 0.883 to 0.916 for the landslide area and from 0.584 to 0.915 for the total area, highlighting the necessity of seasonality adjustment in multi-date vegetation observations using satellite images. Furthermore, the association between precipitation and NDVI was discussed, and the inverse relationship with the reoccurrence of high-intensity short-duration rainfall and yearly heavy rainfall was observed, in agreement with the on-site investigation.

黄土丘陵区植被恢复对土壤可溶性氮组分的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 黄土丘陵区植被恢复对土壤可溶性氮组分的影响 DOI: 10.5846/stxb201603090416 作者: 作者单位: 西北农林科技大学林学院,西北农林科技大学农学院,西北农林科技大学林学院,西北农林科技大学农学院,西北农林科技大学农学院,西北农林科技大学资源环境学院,西北农林科技大学农学院 作者简介: 通讯作者: 中图分类号: s157.5 s714.8 基金项目: 国家自然科学青年基金项目（41301601）；陕西省科技统筹创新工程项目（2015KTCL02-07）；国家自然科学基金项目（41571501） Effects of vegetation restoration on soil soluble nitrogen in the Loess Hilly Region Author: Affiliation: College of Forestry,Northwest A&F University,,,,,,College of Agronomy,Northwest ADdDdF University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探究黄土丘陵地区人工植被恢复对土壤氮素养分累积与有效性的影响，研究分析了植被恢复15年刺槐、柠条、刺槐侧柏混交、刺槐山桃混交以及荒草地土壤可溶性氮组分含量及其垂直分布特征。结果表明，与耕地相比，植被恢复显著提高了0-30 cm土壤可溶性氮组分含量，这也使0-30 cm土壤可溶性氮组分密度显著增加，可溶性有机氮密度增幅表现为柠条（262.2%）> 刺槐（232.8%）> 刺槐山桃混交、刺槐侧柏混交（34.5%） > 荒草地（-21.5%），硝态氮密度整体表现为柠条>刺槐>刺槐山桃混交>荒草地>刺槐侧柏混交，增幅为7.9%-182.8%，铵态氮密度以刺槐山桃混交增幅最大（110.3%），荒草地最小为2.6%。可溶性有机氮、硝态氮占全氮的比例以刺槐最高，分别提升了2.4倍和0.6倍，铵态氮占全氮的比例以刺槐山桃混交最高，提升了1.0倍。可溶性氮组分受微生物量碳氮的影响大于有机质和全氮，微生物量氮与可溶性氮组分的相关性优于微生物量碳，硝态氮对土壤有机质、全氮和微生物量碳氮的变化最为敏感。综上，植被恢复能够提高土壤可溶性氮组分含量、密度及其占全氮比例，增加土壤氮的有效性，以刺槐、柠条提升效果最好。 Abstract:Vegetation restoration has a significant impact on the physical and chemical properties of soil, and can improve soil organic carbon and total nitrogen. Soil soluble nitrogen pools have a major impact on the usually very small but rapidly cycling nitrogen pools such as NH4+-N. Therefore, they will possibly play an important role in the nitrogen transformation pathways and plant uptake. However, the response of soil soluble nitrogen to different vegetation restoration patterns in the Loess Hilly Region of China is still poorly understood. We studied the distribution of soil soluble nitrogen in soil layers at depths of 0-30 cm under five conversion lands: Robinia pseudoacacia (RP), Caragana korshinskii (CK), R. pseudoacacia and Platycladus orientalis mixed forest (RP+PO), R. pseudoacacia and Prunus davidiana mixed forest (RP + PD), and abandoned farmland (AF), which have been converted from slope farmland (SF) for 15 years in the Loess Hilly Region. Contents of soil soluble organic nitrogen (SON), ammonium nitrogen (NH4+-N), and nitrate nitrogen (NO3--N), and their densities and ratio to total nitrogen were determined to investigate the availability of soil nitrogen. Results show that the average contents of SON, NH4+-N, and NO3--N of vegetation recovery lands was significantly higher than that of the slope farmland in the 0-30 cm soil layer (P < 0.05). Compared with other vegetation recovery lands, the SON and NO3--N improvement trend was better for RP and CK in the 0-30 cm soil layer, whereas RP + PD vegetation recovery lands exhibited the most NH4+-N growth. After long-term vegetation recovery, the density of soil soluble nitrogen was also improved. Compared with SF, the SON rates increased in the 0-30 cm soil layer in the following order: CK (262.2%) > RP (232.8%) > RP + PD, RP + PO (average increase rate was 34.5%) > AF (-21.5%). The density of NO3--N in the 0-30 cm soil layer improved from 7.9 to 182.8% in the following order: CK > RP > RP + PD > AF > RP + PO. However, the maximum increase rate of NH4+-N density was seen in RP + PD, whereas the minimum increase rate was seen in AF. Moreover, the ratio of SON and NO3--N to total nitrogen in RP was increased by 2.4 and 0.6, respectively, the ratio of NH4+-N to total nitrogen in RP + PD has increased by 1, as compared to SF. The soil SON was not affected by soil depth, whereas the NO3--N and NH4+-N content decreased with soil depth in the profiles. Further, based on correlation and regression analyses, we found that the soil soluble nitrogen was affected by soil organic matter, total nitrogen, and microbial biomass carbon and nitrogen. However, among these factors, microbial biomass was more sensitive than the others, and microbial nitrogen had a higher influence than microbial carbon. From another perspective, the NO3--N content was sensitive to changes in soil organic matter, total nitrogen, and microbial biomass carbon and nitrogen in long-term vegetation recovery. These findings demonstrate that vegetation recovery can improve the content, density, and proportion of soil soluble nitrogen, and increase the availability of soil nitrogen. It was also observed that converting SF to RP and CK forests is an efficient method of nitrogen activation in the Loess Hilly Region of China. 参考文献 相似文献 引证文献

The change of soil water storage in three land use types after 10 years on the Loess Plateau

Soil water content (SWC) is a critical variable in studies of hydrological processes and the soil–plant–atmosphere continuum, especially in arid and semi-arid regions such as the Loess Plateau. Knowledge of the effects of vegetation types on soil water dynamics would aid in understanding the mechanisms responsible for water shortages and addressing the problem of poor long-term vegetation recovery. To evaluate the response of soil water storage (SWS) to different land use types during long-term natural vegetation succession, we examined soil moisture under different land use types (grassland, shrubland and forestland) at different times (2005 and 2014) in the Ziwuling forest region, located in the central part of the Loess Plateau, China. Our results showed that vegetation type had a significant effect on SWS in the 0–500cm soil layer. The SWS in grassland and shrubland was significantly higher in August 2014 than in August 2005, but the pattern was reversed for forestland. In the same year, the SWS was highest in grassland, intermediate in shrubland, and lowest in forestland. SWS and SWC showed a highly significant and positive relationship in the 0–60cm soil layers (P<0.01), and both soil bulk density (BD) and soil total nitrogen (TN) showed a significant relationship with SWS. In addition, the SWC and soil total porosity (TP) showed a significant positive relationship in the 0–20cm soil layer (P<0.05). These results are expected to provide insights into land water management and inform efforts to estimate the productivity and sustainability of semiarid ecosystems.

A Remote Sensing and GIS Approach to Study the Long-Term Vegetation Recovery of a Fire-Affected Pine Forest in Southern Greece

Management strategies and silvicultural treatments of fire-prone ecosystems often rely on knowledge of the regeneration potential and long-term recovery ability of vegetation types. Remote sensing and GIS applications are valuable tools providing cost-efficient information on vegetation recovery patterns and their associated environmental factors. In this study we used an ordinal classification scheme to describe the land cover changes induced by a wildfire that occurred in 1983 in Pinus brutia woodlands on Karpathos Aegean Island, south-eastern Greece. As a proxy variable that indicates ecosystem recovery, we also estimated the difference between the NDVI and NBR indices a few months (1984) and almost 30 years after the fire (2012). Environmental explanatory variables were selected using a digital elevation model and various thematic maps. To identify the most influential environmental factors contributing to woodland recovery, binary logistic regression and linear regression techniques were applied. The analyses showed that although a large proportion of the P. brutia woodland has recovered 26 years after the fire event, a considerable amount of woodland had turned into scrub vegetation. Altitude, slope inclination, solar radiation, and pre-fire woodland physiognomy were identified as dominant factors influencing the vegetation’s recovery probability. Additionally, altitude and inclination are the variables that explain changes in the satellite remote sensing vegetation indices reflecting the recovery potential. Pinus brutia showed a good post-fire recovery potential, especially in parts of the study area with increased moisture availability.

Changes in species diversity and above-ground biomass of shrubland over long-term natural restoration process in the Taihang Mountain in North China

In order to restore the impaired forest ecosystem in China, great efforts including the banning of the animal grazing and cutting woods for fuel, and implementation of the &amp;lsquo;Grain for Green&amp;rsquo; program have been made by the central and local government of China. The objective of this research was to investigate the changes in above-ground biomass and species diversity after 22 years of vegetation recovery efforts in the lower Taihang Mountain of China. The results indicated that over the natural restoration process shrubs became the dominant species in 2008, while herbs were the dominant species back in 1986. Community coverage, height and above-ground biomass showed significant increases in 2008 compared to 1986. Shrubs showed significant increases in coverage, height, and above-ground biomass, whereas herbs significantly increased in height, but decreased in above-ground biomass. Over the 22-year natural restoration process, the species richness index and the Shannon-Wiener&amp;rsquo;s index had been significantly decreased, whereas the Simpson&amp;rsquo;s predominance index and the Pielou&amp;rsquo;s evenness index had been significantly increased. Long-term vegetation recovery efforts improved the impaired forest ecosystem in lower Taihang Mountain to some extent: significant increases in both community coverage and above-ground biomass. The significant increase in community coverage can reduce the soil loss by wind and water erosion, and increase in the above-ground biomass will improve the soil chemical properties and physical structure. A comprehensive assessment of the success of vegetation recovery should include the evaluation of the changes in ecological process such as soil biological activities in the future research.

Detecting post-fire burn severity and vegetation recovery using multitemporal remote sensing spectral indices and field-collected composite burn index data in a ponderosa pine forest

It is challenging to detect burn severity and vegetation recovery because of the relatively long time period required to capture the ecosystem characteristics. Multitemporal remote sensing data can provide multitemporal observations before, during and after a wildfire, and can improve the change detection accuracy. The goal of this study is to examine the correlations between multitemporal spectral indices and field-observed burn severity, and to provide a practical method to estimate burn severity and vegetation recovery. The study site is the Jasper Fire area in the Black Hills National Forest, South Dakota, that burned during August and September 2000. Six multitemporal Landsat images acquired from 2000 (pre-fire), 2001 (post-fire), 2002, 2003, 2005 and 2007 were used to assess burn severity. The normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), normalized burn ratio (NBR), integrated forest index (IFI) and the differences of these indices between the pre-fire and post-fire years were computed and analysed with 66 field-based composite burn index (CBI) plots collected in 2002. Results showed that differences of NDVI and differences of EVI between the pre-fire year and the first two years post-fire were highly correlated with the CBI scores. The correlations were low beyond the second year post-fire. Differences of NBR had good correlation with CBI scores in all study years. Differences of IFI had low correlation with CBI in the first year post-fire and had good correlation in later years. A CBI map of the burnt area was produced using regression tree models and the multitemporal images. The dynamics of four spectral indices from 2000 to 2007 indicated that both NBR and IFI are valuable for monitoring long-term vegetation recovery. The high burn severity areas had a much slower recovery than the moderate and low burn areas.

Long-term vegetation recovery after vehicle track abandonment on Dartmoor, SW England, U.K.

The use of extensive track networks on northern Dartmoor has caused considerable damage to vegetation during the past 24 years. The number and use of tracks has increased over this period. This paper describes the natural recovery of vegetation on tracks abandoned at several times in the past on five different sites. The undamaged vegetation varies from Agrostis grassland to wet moorland dominated by Calluna vulgaris and/or Molinia caerulea. Analysis of environmental parameters shows that the most recently used tracks suffer compaction and reduced soil depth and moisture. Canonical Correspondence Analysis (CCA) is used to explore these effects further, and the way in which vegetation can be expected to change over time is deduced from comparison of tracks of different “ages” as a “time-track” on an ordination diagram. Recovery may be rapid in grassland and heathland sites but areas of higher moorland and blanket bog recover more slowly and may never revert to their original vegetation composition. The results are discussed with respect to practical conservation management of the area.

The response of semi-arid vegetation assemblages following the abandonment of mining towns in south-western Montana

Abandoned mining towns provide an excellent opportunity to examine long-term vegetation recovery processes. Analysis of data collected in five ghost towns in semi-arid south-western Montana indicated considerable differences remain after 45–77 years of recovery. Two measures of vegetation recovery, introduced grass cover and species richness, differed markedly between undisturbed sites and disturbed sites at four of the towns. Disturbances favoured the invasion of introduced grasses and greater species diversity. At the fifth town, the driest location, the presence of a native sod grass, Bouteloua gracilis , which can withstand severe disturbances, apparently inhibited the establishment of non-native species, thereby hastening the recovery process.